1. Field of the Invention
The present invention relates to acid compositions that are useful in food, medical, commercial and military industries and also as general household products. These compositions have a low pH, are relatively non-corrosive to metals, do not harm skin and are safe for use in food and beverages. The invention also relates to formulations that contain these acid compositions and to methods for using such formulations.
2. Description of the Background
Low pH compositions and solutions containing acidic compositions are used for various industrial and general household purposes, such as cleaning and sterilizing surfaces and articles of manufacture. Examples include well-known household cleansers and disinfectants, industrial microchip production and cleaning agents, and anti-microbials. To work both effectively and efficiently, these solutions typically contain strong acids or organic solvents, which present health concerns to the user, may be corrosive to the substances they are designed to clean (e.g. metals) and pose an ecological hazard with respect to disposal.
There have been a number of efforts aimed at developing less corrosive and less toxic acidic products. For example, U.S. Pat. No. 4,459,202 is directed to an acidic composition for recovering bituminous products from tar sands. Two strong and two weak acids are combined to form an acidic solvent that can be used to remove and recover the bituminous products. The composition is described as being non-corrosive and less hazardous to handle than other strongly acidic solutions.
The molecular effect of combining first and second strong acids with the third and fourth weaker acids forces the weaker acids to act as conjugate bases for the strong acids and to accept hydrogen ions (actually hydronium ions in aqueous solution) from the strong acids. The resulting acidic solution has a very low pH value, and a large amount of free hydrogen ions. However, the ability of this strong acidic composition to effectively function as a solvent may sometimes require more acid than would be considered safe or non-hazardous to human tissue. Moreover, there is no suggestion that this composition can be used in other applications, such as in products which come into contact with food. In fact, the composition cannot be used in connection with food and drink, as one or more of its components are not listed on the U.S. Food and Drug Administration list of substances considered generally recognized as safe (GRAS).
Various formulations using multiple acid compositions are disclosed in U.S. Pat. Nos. 4,675,120, 4,970,014, 4,970,015 and 5,019,288. Each of these compositions is described as either useful for well-acidizing, tertiary oil recovery, removing rust from metal, cleaning aluminum, radiator cleaning, boiler and heat exchanger cleaning, or copper cleaning. These compositions are described as generally non-corrosive to metal and relatively inert when contacted with human tissue. In addition, U.S. Pat. No. 4,483,887 describes a multiple acid solution useful for metal plating. U.S. Pat. No. 4,477,364 describes a multiple acid solution useful for cleaning glassware.
Although these acid-based solutions may be effective for the various described purposes, a major drawback is that certain formulations can cause skin irritation. For example, studies conducted using a topical skin disinfectant containing the core composition of U.S. Pat. No. 4,459,202 found that the product caused reddening of the skin and a burning sensation. Similar reddening of the skin and burning sensation resulted with a cleaning solution containing the core acid composition of U.S. Pat. No.4,459,202. As such, these acid compositions cannot be safely used in products where skin contact is a possibility. In addition, such compositions cannot be used in products associated with foods or beverages. Further, many of these compositions require a multiplicity of components, leading to increased production costs.
U.S. Pat. No. 5,512,200 is directed to a multiple acid composition described as non-irritating to the skin and useful as a component of products such as cleansers, cosmetics and pharmaceutical agents. However, at least one of the components is not considered GRAS. Thus, despite the relatively inert nature of this composition, it cannot be used in foods or drinks, or in products associated with foods or drinks.
There is therefore a need for acid compositions comprising a minimum number of component acids, all of which components are approved by the Food and Drug Administration as GRAS, with broad utility for cleaning, sterilizing and anti-microbial uses that are effective, non-toxic and safe for use with food and food-related products.
The invention overcomes the problems and disadvantages associated with current strategies and designs and provides novel low pH compositions useful in medical, military, industrial and household settings. These acid compositions can be used as the sole or core component of solutions including cleansers, anti-microbial agents, disinfectants, decontaminants, pharmaceuticals, cosmetics, anti-odor agents and sterilants.
The low pH compositions of the present invention are safe for use as either the sole or major component of solutions including, but not limited to, disinfectants, cleansers, sterilizers, cosmetics, and pharmaceutical agents, and can be used in industrial, medical, military and general household settings. The compositions of the present invention are safe not only for use in products which contact human skin, but also for use in ingestible products.
One embodiment of the invention is directed to an acid solution for inhibiting microbial growth comprising an aqueous acidic core composition which makes up 50% to 100% of the solution. The acidic core composition consists of acids that are safe for use in food and drink products and food- and drink-associated products (i.e. GRAS substances). The acidic core composition may be prepared by admixing from about zero to about 25%, by volume, of a first acid, preferably between about 0.1% to about 15%, and more preferably between about 0.5% and about 10%, with between about 1% and about 25%, by volume, preferably between about 2% and about 15%, and more prferably between about 5% and about 10%, of a second acid to produce a first acidic composition.
The first acid is an inorganic acid that dissociates nearly to completion in water. The second acid is an inorganic acid less strong than the first, having a dissociation constant of less than about 10xe2x88x921. A second acidic composition is formed by mixing from about 0.5% to about 20%, by weight, preferably from about 2% to about 15%, and more preferably from about 6% to 10%, of an organic hydroxy acid with water. The organic hydroxy acid has a greater chelating capability (generally at least twice) or iron binding efficiency as one or the other of the first and second inorganic acids. Acids with at least twice the ion binding efficiency of the inorganic acids include, for example, ascorbic acid, citric acid, lactic acid, malic acid and taltaric acid.
The two acidic compositions or solutions are then mixed to produce an acid core composition that inhibits microbial growth and is safe for use in food products. This composition preferably has a pH of less than one, yet will not adversely react with human tissue.
In a preferred embodiment, the first acid is hydrochloric acid, the second acid is phosphoric acid, and the organic hydroxy acid is citric acid. Generally, the quantities of the first acid will balance the quantity of the second acid such that less of the first acid will be required when using more of the second acid. A maximum quantity of the second acid is that amount which will require the addition of no first acid when admixed with the organic hydroxy acid to produce the low pH composition of the invention.
The acid composition of the present invention maintains the low pH and non-toxic qualities of conventional acidic compositions, yet, unlike these compositions, is safe to use in food and food-associated products, such as paper for packaging and wrapping food, food containers, food preserving agents and ingestible products.
In contrast, acids used in a number of conventional products, such as, for example, hydrofluoric, sulfuric, nitric, chloric, perchloric, chlorous, hydrofluoric, hydrosulfuric, fumaric, oxalic, phthalic, tartaric, acetic, acrylic, benzoic and carbonic acid, are not generally recognized as safe, and none are federally approved for use in ingestible products or products contacting ingestible products. Further, as many of the conventional acid-based solutions are toxic, disposal and handling of such compositions require special measures not necessary when utilizing compositions of the invention.
Another embodiment of the invention is directed to a pharmaceutical compound comprising a three acid composition, the three acid composition comprising: a first acid, wherein the first acid is an inorganic acid that dissociates nearly to completion in water; a second acid, wherein the second acid is an inorganic acid less strong than the first inorganic acid and has a dissociation constant of less than about 10xe2x88x921; a third acid, wherein the third acid is an organic hydroxy acid which is weaker than the first and second acids, has a greater chelating capacity, generally at least twice, of either first or second acid, and has a dissociation constant of from about 10xe2x88x921 to 10xe2x88x925; and a pharmaceutical agent. Preferably, the three acids are GRAS acids.
Another embodiment of the invention is directed to a composition for processing food items comprising a three acid preservative consisting of: first inorganic GRAS acid that dissociates nearly to completion in water; a second inorganic GRAS acid less strong than the first acid and having a dissociation constant of less than about 10xe2x88x921; and a third GRAS acid, the third GRAS acid being an organic hydroxy acid that has at least twice the chelating efficiency as either of the inorganic acids. Preferably, the organic hydroxy acid is weaker than the first and second acids and has a dissociation constant of from about 10xe2x88x921 to 10xe2x88x925. An especially preferred food processing composition comprises hydrochloric, phosphoric and citric acids.
Another embodiment of the invention is directed to a method of preserving food comprising the addition of a three acid preservative composition to a food substance.
The three acid preservative composition comprises: a first GRAS acid which is an inorganic acid that dissociates nearly to completion in water; a second GRAS acid, the second GRAS acid being an inorganic acid less strong than the first GRAS acid and having a dissociation constant of less than about 10""1; and a third GRAS acid, the third GRAS acid being an organic hydroxy acid weaker than the first and second GRAS acids, with chelating capability at least twice as great as either or both of the first and second GRAS acids and a dissociation constant from about 10xe2x88x921 to 10xe2x88x925.
Another embodiment of the invention is directed to a method for decontaminating surfaces comprising contacting the surface with an acid composition of the invention comprising: a first GRAS acid, wherein the first GRAS acid is an inorganic acid that dissociates nearly to completion in water; a second GRAS acid, wherein the second GRAS acid is an inorganic acid less strong than the first inorganic acid and has a dissociation constant of less than about 10""1; and a third GRAS acid, wherein the third GRAS acid is an organic hydroxy acid weaker than the first and second GRAS acids, but being at least twice as efficient as either or both of the first and second inorganic acids in its chelating ability and having a dissociation constant of from about 10xe2x88x921 to 10xe2x88x925.
Another embodiment of the invention is directed to a method for treating a surface to inhibit microbial growth on the surface comprising contacting the surface with a three acid composition according to the invention.
Other objects and advantages of the invention are set forth in part in the description which follows, and in part, will be obvious from this description, or may be learned from practice of the invention.
As embodied and broadly described herein, the present invention is directed to low pH acidic compositions that are generally recognized as safe. Compositions according to the invention are safe for use in food, beverage, or other ingestible products and do not irritate the skin. The present invention is useful in industrial, medical, military, and household applications. Medical applications include use on humans and animals. The invention also relates to formulations containing the acidic compositions of the invention, applications of these compositions, and to methods of making and using these compositions.
Many of the acidic compositions currently used in industrial, medical, military and household settings present health hazards to the user and are corrosive with prolonged exposure to the surfaces they contact. Use of these compositions often requires special protective clothing and application methods. Additionally, disposal of these toxic products in a manner which ensures the safety of the environment and personnel is costly and time consuming. Although some conventional compositions are less caustic to skin and, overall, less hazardous to the user than others, they are, nonetheless, not safe for use in food and beverages or in other ingestible products.
An acid composition that can be safely handled and applied directly to human skin has been discovered which, unlike conventional acid-based compositions, uses a minimum number of ingredients, all of which are federally approved for use in food and drink products and food- and drink-associated products. Compositions of the invention are also applicable for industrial, military and general household uses. In addition to being suitable for use on and by humans, the present invention is also appropriate for animals. The compositions of the invention are effective and may be used over a wide range of temperatures, including room temperature. Thus, the present invention provides an advantage over sterilants which require a power source or energy, such as beat (autoclaving). Moreover, acid compositions of the invention have a shelf life of one year or greater when stored at ambient temperature.
One embodiment of the invention is directed to a low pH acid composition comprised only of GRAS substances. GRAS substances are those substances which are approved for use in food, beverages and other ingestible products, and in products which contact these materials. Specifically, these substances, listed at 21 C.F. R. Part 182 and Part 184, are recognized by the FDA as safe for use in foods, beverages and ingestible products, and in products associated with foods and beverages. Such substances are generally considered non-carcinogenic. As such, the compositions of the invention are safe to use in association with food and drinks and other ingestible products.
In a preferred embodiment, three acids are used. The first acid is hydrochloric acid, the second acid is phosphoric acid, and the third acid is citric acid. In this embodiment, the first acid of the composition, hydrochloric acid, comprises between about zero to about 25 volume percent of the final composition, preferably between about 0.1 to 20 volume percent, and more preferably between about 5 to about 10 volume percent of the final composition. Hydrochloric acid is a strong inorganic acid which dissociates nearly to completion in water. Some particularity useful acid compositions of the invention contain about 0.1%, 0.2%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 8%, 10%, 12%, 14%, 15%, 18%, 20%, 21%, 22% and 24% of the first acid.
The second acid of the composition, phosphoric acid, is also an inorganic acid but is less strong than hydrochloric acid. Phosphoric acid thus functions as a conjugate base and accepts hydrogen ions (actually hydronium ions in aqueous solutions) from the stronger hydrochloric acid. The phosphoric acid comprises between about 0.1 to about 20 volume percent of the final composition and preferably between about 1 to 15 volume percent, and more preferably between about 5 to about 10 volume percent of the final composition. Some particularity useful acid compositions of the invention contain about 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 8%, 10%, 12%,13%, 14%, 15%,16% and 18% of the second acid.
The third acid is an organic acid (e.g. citric acid) belonging to the group of hydroxy carboxylic acids and is a weak acid relative to hydrochloric and phosphoric acids. Specifically, citric acid is a 6-carbon, tricarboxylic acid. Citric acid preferably comprises between about 1 to about 15 weight percent, preferably between about 5 to about 10 weight percent and more preferably between about 6 to about 9 weight percent of the final composition. Some particularity useful acid compositions of the invention contain about 0.5%, 1%,2%,3%,4%,5%,6%,8%, 10%, 12%, 13%, 14%, 15%, 16%, 17%, and 18%, by weight, of the organic hydroxy acid.
A preferred embodiment of the improved aqueous acidic composition of the invention may be prepared by a process involving the following steps:
(1) mixing at room temperature from about 5 to about 10 (most preferably 6.60) volume percent hydrochloric acid (HCl being principally responsible for the resulting pH) with from about 1 to about 5 (most preferably 4.49) volume percent phosphoric acid in a first container for a period of time sufficient to produce a homogenous mixture;
(2) mixing at room temperature in a second container from about 5 to about 10 (most preferably 7.50) weight percent citric acid with from about 85 to about 90 percent water for a period of time sufficient to result in thorough mixing; and
(3) admixing at room temperature the hydrochloric/phosphoric acid mixture held in the first container into the citric acid/water mixture of the second container until a homogenous composition results.
The acid aqueous composition of the present invention is basically colorless (high concentrations of HCl produce a greenish to yellowish color), has a pH of less than one, will not harm human tissue, and contains only substances approved by the Food and Drug Administration to be GRAS substances. Thus, the resulting aqueous acidic composition is safe for use in food, drink, and other ingestible products. The composition of the present invention is also much less corrosive to metals than acid compositions at a similar pH. Delicate instruments such as, for example, dental instruments, surgical and other medical instruments, and computer parts, can be effectively cleaned using an acid composition of the invention without harming the delicate components or parts of the instrument or causing undue wear.
The acid composition of the present invention may be used alone or as the base, core or active component in the formulation of other solutions. Additional ingredients, if desired, may be added to the three acid composition depending on its intended purpose or application. Substances may be added to the core acid composition, for example, to increase the retention time of the product on the skin, to give an appealing color or scent to the composition, to produce a specific texture, or to increase the specificity of application of the composition. Additives such as anesthetic agents (e.g. lidocaine), pH indicator dyes and other dyes and contrast agents can be added depending on the application.
The compositions of the present invention are suitable for use in a plurality of food industry, household, military, medical and industrial settings. Just a few potential uses of the compositions of the present invention include: cleaning and disinfecting surfaces, instruments, foods and equipment; antimicrobial component for hygiene products, preparation of skin surface for injections, topical ointments, creams, gels, inhalants (generally used at concentrations of 5%, 4%, 3%, 2%, 1% or less), mouth and eye washes, activation of immune-response (e.g. stimulates non-specific immunity); anti-odorant; cleaning and disinfecting food items and food processing (e.g. removes coffee and tea stains), packaging and storage materials; pH- and/or microbial-control agent (swimming pools); a detoxifying/decontaminating composition for clean up of chemical spills or hazardous materials (HazMat) (decontamination showers) (eliminates toxic cloud/fumes from acid spills at various mixtures such as 10:90, 25:75, 60:40, 50:50, 40:60, 75:25 and 90:10 mix depending on the acid); manufacture of food processing, packaging and transportation items; detoxifying composition for industrial settings (i.e. paper mills and other industrial plants, and laboratories may use HCl and/or sulfuric acids; can treat HCl burns with invention); industrial showers (acid showers); manufacture of acid-containing solutions and products (i.e. batteries containing xe2x80x9cbattery acidxe2x80x9d such as sulfuric acid; by mixing with invention, less toxic and less fuming); cleaning battery posts; sterilization or purification of water supply; non-toxic embalming agent; detoxification/deactivation of chemical and biological warfare agents; and cleaning air ducts.
Specific veterinary, dental and medical applications include wound cleaning and disinfecting, disinfecting and sterilizing floors, surfaces and instruments (dialysis apparatus), topical treatment of skin infection, treatment of topical irritants (poison ivy and poison oak), sterilization of indwelling devices (e.g. catheters, IV drips); anti-STD applications (i.e. suppositories, creams, gels, condoms, mouthwashes, douches); treatment of burns, sunburns, ear infections, insect bites, jellyfish stings, anti-coagulant, treatment of medical waste, and anti-fungal agents (e.g. anti-jock itch treatment, prevention or treatment of athlete""s foot).
The invention can also be used as an anti-odorant to neutralize ammonia-based odors/wastes, biological specimens, chemical toilets, animal bedding and diapers. It may be used as an underarm deodorant. In connection with food, it may be used to spray produce, clean and disinfect food transport containers and fluid lines or any surface coming in contact with food and food serving materials. It may be applied to seafood as a deodorizer and be used to spray live animals or to spray meat before wrapping, etc. As an antibacterial, anti-fungal and sporicide, it may be used, for example, as an acidifier in home canning.
With respect to military applications, the invention may be used to decontaminate chemical warfare agents on personnel and surfaces, and given its broad spectrum of activity, is ideal for incorporation into bandages and sponges. The invention may be incorporated into a missile or other delivery device as a countermeasure to deactivate chemical warfare or biological agents (e.g. protein toxins such as anthrax, botulism and E. coli) delivered by or contained in another weapon system. It may be delivered to a broad contaminated area through the use of a fog/smoke generating device, crop-dusting or firefighting aircraft.
Applications also include use as a non-toxic embalming agent, anti-scale build-up and treatment of water supplies, electrolyte sports drink, treatment of personal items such as toothbrushes or hairbrushes, safety showers for certain industries using acids, acid spill or acid cloud clean up. It may be used as a silver or chrome polish, to remove oxidation build-up on heat exchangers, pipes and water heaters, to descale sinks, water storage tanks, showers and the like to remove barnacles, or to clean concrete. It may be used as a fixative for fabric dyes (pH indicator dyes bonded to cotton fabricsxe2x80x94dye retained after machine laundering; also may be used in wearable pH indicator garments which are acid or base sensitive). It may be used as a preservative for foods, biological specimens, forensic specimens and biological specimens and lumber. It may be used as a buffer for noxious solutions or to inhibit the corrosive properties of bleaching solutions. Further applications include etching aluminum or porcelain, and use as an anti-freeze or water purifier. Because the invention is compatible with pH indicator dyes, solution efficacy can be visually determined. Also, solutions have the potential for repeated re-use (i.e. can be recycled).
Another embodiment of the invention is directed to a pharmaceutical agent or compound containing the acid composition of the present invention. As will be clear to those of skill in the art, various substances may be added to the aqueous acidic composition of this invention as desired to produce a pharmaceutical agent. The terms xe2x80x9cpharmaceutical agentxe2x80x9d or xe2x80x9cpharmaceutical compoundxe2x80x9d as used herein are used in their broadest possible sense and include, but are not limited to, medications and all types of therapeutic agents, whether taken orally, parenterally, topically, or by any other route. Useful substances which may be added to produce a pharmaceutical agent include, but are not limited to, anesthetic agents, alcohols, creams, gels, aloe vera, vitamin E, PFP (polyfluorenated perfluorate, e.g. TEFLON, FOMBLIN), moisturizers, emollients, surfactants, humectants, scents, colorants, glycerin, propylene glycol, emulsifiers, wetting agents, pH indicator dyes, medically-relevant dyes, contrasting agents, and carriers known in the art. Uses of the pharmaceutical agents or compounds formulated with the three acid composition include, but are not limited to, deodorants, mouthwashes, topical antimicrobial ointment for wounds, and compositions for the treatment of a wide variety of maladies, including dry skin, wrinkles, acne, age spots, sunburn, infections (viral, bacterial and fungal), insect bites and rashes. The pharmaceutical agent may be appropriate for use on mucous membranes, including the mouth and eyes. The pharmaceutical agent or compound can be brought into contact with the surface to be treated either directly or via applicators, including, but not limited to, sponges, towelettes and pads.
Another embodiment of the invention is directed to decontamination agents containing acid compositions of the invention. These agents are particularly useful in military and industrial applications. These decontamination agents provide protection from, or directly inactivate, a variety of toxic chemical agents, such as those used in chemical warfare, farming, and lawn care. Such toxic chemicals include, but are not limited to, insecticides, pesticides, mustards, nerve agents, blister agents, cholinesterases and cholinesterase inhibitors in general. Additionally, decontamination agents according to the invention are effective in the inactivation of biologically toxic molecules such as those used in warfare. Biologically toxic molecules include, but are not limited to, aflatoxins, biological toxins, exotoxins, endotoxins, poisons, phytotoxins, insect and animal venoms and mycotoxins. Because of the non-caustic nature of the acid compositions of the present invention, these decontamination agents may be applied either directly to the skin, or may be applied to clothing or other materials that come in contact with skin. Thus, the present invention is suitable for use by first-responders in decontaminating physical surfaces, treating wounds in humans or animals, and/or deactivating chemical agents including nerve agents.
In a preferred decontamination compound, a three acid composition is made into a reactive topical skin protectant which may be mixed with a perfluorinted polyether grease vehicle, a water-based vehicle, or other suitable vehicle. Use of alternative vehicles allows for flexibility in application of the topical protectant. The resulting decontamination/protection barrier is active over a broad temperature range of from about xe2x88x9210xc2x0 C. to about 50xc2x0 C., and is stable for one year or longer when stored at ambient temperatures.
Another preferred embodiment is directed to a decontamination compound in which the acid composition is incorporated into towelettes or sponges. The use of these towelettes or sponges allows for safe and rapid detoxification of organophosphate compounds (e.g. nerve agents), as well as viruses, bacteria and toxic molecules. The towelettes or sponges are easily carried by personnel and used by first-responders in decontamination steps. The towelettes or sponges are active over a broad temperature range of from about xe2x88x9210xc2x0 C. to about 50xc2x0 C., and have a shelf life of one year or longer.
Another embodiment of the invention is directed to cleansing agents containing the acid composition. These cleansing agents include, but are not limited to, glass cleansers, metal cleansers, household cleaning solutions (kitchen and bathroom), and solutions to remove oxidation build-up from pipes and water heaters and heat exchangers. In this use of the invention, detergents, soaps, scents or strong acids may be added as needed to the acid composition.
In a preferred cleansing agent, hydrochloric acid is added to the acid composition in ratios ranging from about 0.1 parts to 30 parts (by volume) of the acid composition to produce a solution suitable for use as a metal cleaner. Addition of more hydrochloric acid reduces the time required for cleaning; however, this may result in a product which irritates skin.
Another embodiment of the invention is directed to the use of the invention as an antimicrobial agent such as a disinfectant or sterilant. These disinfectants and sterilants may be used, for example, to sterilize drinking water, disinfect surfaces, treat wounds, sterilize hair care and manicure equipment, sterilize dental equipment, sterilize hospital clean rooms, sterilize tissue culture hoods in laboratories, and sterilize biological waste. The three acid composition of the present invention may also be used in cleaning or sterilizing containers used in the transportation and storage of food and drink, such as truck tanks, vats and fluid lines.
Substances including, but not limited to, perfumes, aerosols, dyes, alcohols, reducing agents, anesthetic agents, oxidizing agents, amines, amides, surfactants, creams, gels and other acids may be added to the compositions of the present invention as needed for a particular application.
Another embodiment of the invention is directed to a composition for processing food comprising a three acid preservative consisting of a first inorganic GRAS acid that dissociates nearly to completion in water, a second inorganic GRAS acid having a dissociation constant of less than about 10xe2x88x921, and a third GRAS acid being an organic acid weaker than the first and second acids, and having a dissociation constant of from about 10xe2x88x921 to 10xe2x88x925. An especially preferred food processing composition comprises hydrochloric, phosphoric and citric acids.
Food processing compositions of the present invention may be suitable for decontaminating food items, such as, for example, meats, fruits or vegetables. In a preferred embodiment, the composition is applied to fruits and/or vegetables to remove or effectively destroy residual pesticides. The food processing composition may also be suitable for use as a de-odorize for seafood and as an antimicrobial treatment for meat products.
Another embodiment of the invention is directed to a method of preserving food comprising the addition of an acid preservative composition to a food substance, the acid preservative composition containing a first GRAS acid, the first acid being an inorganic acid that dissociates nearly to completion in water; a second GRAS acid, the second acid being an inorganic acid less strong than the first inorganic acid and having a dissociation constant of less than about 10xe2x88x921; and a third GRAS acid, the third acid being an organic acid weaker than the first and second acids, the third acid having a dissociation constant of from about 10xe2x88x921 to 10xe2x88x925.
The above formulations and applications are intended to merely illustrate the wide range of utility of the compositions described herein and are not intended to be an exhaustive listing of all possible formulations and uses of compositions according to the invention. Also, as the list of substances approved by the U.S. Food and Drug Administration to be Generally Regarded As Safe (GRAS) is revised, so will be the acids available for use in the compositions of the invention. As will be clear to those of skill in the art, compositions that are safe for human ingestion or contact are likewise safe for ingestion or contact by other animals.
The following examples are offered to illustrate embodiments of the present invention, but should not be viewed as limiting the scope of the invention.